Cellular mobile telephone services have been in operation in many parts of the world for several years and within the continental United States for nearly a decade. Cellular mobile telephone service is currently one of the most rapidly expanding types of communication services. The structure and general operation of several types of commercially available cellular mobile telephone systems is well documented in the patent and communication arts literature. One seeking a description of some representative types of equipment should see: U.S. Pat. No. 4233273 entitled Comprehensive Automatic Mobile Radio Telephone System; U.S. Pat. No. 4776003 entitled Cellular Mobile Radio Credit Card System; U.S. Pat. No. 4958368 entitled Customer Activation System; The Cellular Mobile Radiotelephone by Stephen Gibson, 1987, Prentice-Hall; or The Cellular Connection by Joseph Bernard, 1987, Quantum Publishing.
All of the prior art mobile telephone systems and particularly those in a multi-channel mobile radio telephone system involving a plurality of various carrier companies having a plurality of base stations covering different geographic areas have encountered substantial difficulties in attempting to provide telephone services which are comparable to facilities and services available to fixed or immobile telephone stations. As is well known to telephone subscribers in the United States, fixed telephone stations in the United States and in most developed countries for many years have provided practically instantaneous access to direct distance dialing networks and subscribers can dial calls to practically any fixed substation within the telephone network, and likewise receive calls from any fixed substation in the network; all without the assistance or intervention of a telephone operator. Multi-channel radio telephone systems have further problems, including substantial losses incurred with fraudulent theft of services. The fraudulent theft of services is attributable in large part to the movement of mobile subscribers from their home areas across the country, commonly referred to as "roamers". These operating problems are further complicated by the commercial objectives of the mobile telephone service companies in attempting to provide expanded services, including the ability of roamer mobile subscribers to freely and quickly automatically originate and receive calls to and from any other fixed or mobile stations in the network.
The growth and expansion of the cellular telephone usage since its inauguration in the Continental United States in 1983 continues at a rapidly expanding rate.
As of November 1991, there were more than 6.3 million cellular telephone subscribers in the Continental United States, and in the fall of 1991 cellular telephone service was available in all 306 metropolitan statistical areas across the Continental U.S., and the Federal Communications Commission is rapidly completing the licensing process for the so-called Rural Service Areas. Thus, with the rapid growth of cellular telephone technology and the substantial reductions in the size and price of cellular phones, the cellular telephone system will continue to rapidly expand and in the near future it will be available throughout the entire North American continent and expand rapidly into all of the developed countries of the world.
Fraudulent use or theft of service is one of the principal business and technical problems faced by cellular telephone service companies today and in the Continental United States is estimated to result in a loss on the order of $600 million for these companies. Fraudulent user is a term used by the cellular telephone industry to denote anyone who seeks to obtain or obtains cellular telephone services without authorization from the service provider companies. Fraudulent use of a cellular telephone can take several forms. For example: First--theft of a mobile telephone and subsequent unauthorized use in the same or different geographic area with the subsequent unauthorized user masquerading as the valid subscriber. Second--cloning or duplicating a valid mobile telephone by securing a valid mobile telephone subscriber's authorization data, including for example the Electronic Serial Number (ESN)--Mobile Identification Number (MIN) pair data either by purchase from service or installation personnel or by surreptitiously recording the ESN-MIN data while the valid user is transmitting or by electronically copying or duplicating the ESN-MIN data from a stolen mobile phone unit into one or more other cellular phone units. Third--fraudulent use of cellular phone services may involve the use of random, unauthorized ESN-MIN data which could be randomly generated by a data sequence generator to attempt to gain fraudulent access to mobile telephone services. Finally, hijacker or subscription fraud schemes generally involve an increase in the fraudulent user's phone power level in order to take over a legitimate mobile radio traffic channel assigned by the service provider company to another mobile subscriber.
U.S. Pat. No. 4955049 describes a fraud detection system which involves generating, in connection with the accounting and billing records of an authorized subscriber, a call sequence list which permits a legitimate subscriber to differentiate between authorized calls initiated by the subscriber and fraudulent calls made by an unauthorized party by using the ESN-MIN pair of the legitimate subscriber. This call sequence process does not detect the fraudulent use before mobile service is granted, but only distinguishes on a subscriber's mobile telephone bill between authorized and unauthorized calls. Further, active work on cellular fraud by various Telecommunications Industry Association members and committees as evidenced by EIA/TIA IS-41, Rev. B Draft Standard and EIA/TIA IS-54, Rev. B Draft Standard and suggested extensions of both, and other reports depend almost exclusively on the existence of a communications path, common IS-41B protocols, and a rapid response for queries of roamer status sent by visited networks to the roamer's home network. Unfortunately, current cellular systems, including IS-41 protocol, do not facilitate the detection of the most common types of mobile telephone fraud as described above and more importantly do not provide a process or apparatus for effectively sharing among local mobile telephone service providers current data regarding newly authorized ESN-MIN and/or stolen mobile phone data in order to facilitate detection of such fraudulent usage before service is granted. In addition to being dependent upon a network not controlled by cellular operators, it is highly questionable whether the future networks and accompanying IS-41 and IS-54 protocols, even when widely implemented, will be able to provide a grade of service to allow for effective fraud reduction.
As is known to those skilled in communication arts, the business and commercial objective of cellular telephone service companies has been to offer fast, convenient service to mobile users which is increasingly comparable with the services offered to fixed or immobile stations and provides practically instantaneous access to all direct dial networks. These commercial objectives have in a sense facilitated a number of types of cellular telephone fraud since the currently existing cellular telephone system protocols and clearinghouse and accounting and billing procedures utilizing services offered to the industry by two companies, namely GTE Telecommunications Services Inc., 100 S. Ashley, Tampa, Fla. 33602, and EDS Personal Communications Corp., 1601 Trapello Road, Waltham, Mass. 02154, do not provide anything like on-line real time responses, but instead require an inordinate time to process requests. Similarly, these current industry procedures referred to above do not provide any commercially secure procedure to encourage competitive companies to exchange any current customer authorization status data sufficient to detect and prevent fraudulent use of cellular telephone services before service is granted.